Unit 6 (Notes & Review Sheet) Flashcards
3 stages of cellular respiration
glycolysis
citric acid cycle
oxidative phosphorylation
reactants of glycolysis
glucose (6C)
products of glycolysis
2 molecules of pyruvate (3C)
2 ATP
2 NADH
glycolysis occurs in
cytoplasm
reactants of citric acid cycle
2 pyruvate / acetyl CoA
products of citric acid cycle
2 ATP
6 NADH
2 FADH2
CO2
citric acid cycle occurs in
the matrix of the mitochondria
reactants of oxidative phosphorylation
electrons from NADH & FADH2
products of oxidative phosphorylation
32 ATP
oxidative phosphorylation occurs in
the membrane of the mitochondria
Glycolysis means
splitting of sugar
what is glucose cut in half to produce
pyruvate
what molecules are reduced during glycolysis
NAD+ are reduced to NADH
an enzyme transfers a phosphate group to an ADP creating ATP
substrate level phosphorylation
what is produced by substrate level phosphorylation in glycolysis?
2 ATP
is the enzyme changed during substrate level phosphorylation
no
what type of reaction is glycolysis?
exergonic- the chemical energy of bonds in glucose is transferred and stored in the chemical bonds of ATP - it’s a product being released
how many total ATP are produced during glycolysis?
4
how many net ATP are produced during glycolysis?
2 (4 total minus 2 input)
what happens to pyruvate after glycolysis and before the citric acid cycle?
it gets a hair cut in which it loses a carbon and gains a coenzyme
what molecule gets reduced during the citric acid cycle?
NAD+ to NADH
what is the new version of pyruvate?
acetyl CoA
what does CoA stand for?
coenzyme A
how does acetyl CoA enter the mitochondria?
transport protein
what are the byproducts of pyruvate to acetyl coa?
CO2 & NADH
how many atp are produced w each turn of the citric acid cycle?
1
how many nadh and fadh2 are produced w each turn of the citric acid cycle?
3 nadh
1 fadh2
what is the function of nadh and fadh2?
to hold electrons for the next step in cellular respiration
how many molecules of acetyl coa enter the cycle?
2
how many nadh are generated from pyruvate to acetyl coa conversion?
2
whats the reason behind the name of oxidative phosphorylation?
oxidative- electron carriers are oxidized and oxygen is present
phosphorylation- ADP and P connect in chemiosmosis to form ATP
what are the two sub-steps in oxidative phosphorylation?
electron transport chain (ETC) and chemiosmosis
what are the folds of the mitochondria
cristae
how does form fit function in the mitochondria
the many folds of the inner mitochondrial membrane increase the surface area for many copies of the ETC
what happens to the electrons in nadh and fadh2 in oxidative phosphorylation
the electrons leave the carrier molecules and move through proteins in the membrane (energy staircase)
what is the final electron accepter
oxygen
how does H+ get across the membrane and in which direction does it go in the ETC?
energy released from electron movement is used to actively transport H+ across the membrane from the matrix to intermembrane space/low to high concentration
what is the second step of oxidative phosphorylation?
chemiosmosis
what does chemiosmosis use from the ETC?
it uses the potential energy stored by the H+ gradiet produced in ETC
what is the mini turbine that uses the potential energy of the H+ gradient?
ATP synthase
what does the atp synthase do
it rotates to activate the site on synthase that phosphorylates ADP to generate ATP
what poisons block electron carriers so that they aren’t getting to oxygen, then no H+ gradient is generated, and so no ATP is made?
rotenone, cyanide, and carbon monoxide
what does oligomycin do
it inhibits ATP synthase. it is used on the skin to kill fungal cells. because it can’t get past the outer layer of dead cells, the living cells are protected
what do uncouplers do
they make the membrane of the mitochondria leaky to H ions. ETC still happens, but not chemiosmosis
Glycolysis
First stage of cellular respiration. Means “splitting of sugar”.
Glucose
The reactant in the process of glycolysis.
Products of glycolysis (including net ATP)
4 molecules of ATP, 2 molecules of NADH, and 2 molecules of pyruvate.
Where glycolysis occurs
Cytoplasm
Substrate level phosphorylation
Process in which an enzyme transfers a phosphate group from a substrate molecule directly to ADP, forming ATP
Stages where substrate level phosphorylation occur
Glycolysis and citric acid cycle
What happens to pyruvate before it enters the cycle?
Carboxyl group removed from pyruvate, pyruvate is oxidized, Coenzyme A joins pyruvate to form acetyl CoA.
How does pyruvate enter the citric acid cycle?
Goes into mitochondrion through a transport protein, into matrix, enzymes strip acetyl CoA of coenzyme A, enters the cycle
Cycles of citric acid cycle per glucose molecule
2
Reactant of citric acid cycle
Acetyl CoA
How are breathing and cellular respiration related?
Breathing brings o2 to the cells where the mitochondria use it for cellular respiration.
Overall chemical reaction of cellular respiration
Glucose (C6H12O6) + 6 oxygen gas (O2) = 6 carbon dioxide (CO2) + 6 water (H20) + energy (ATP
What are redox reactions?
a chemical reaction in which electrons are lost from one substance (oxidation) and added to another (reduction). oxidation and reduction always occur together.
What is oxidation?
loss of electrons
What should you realize about oxidation?
As electrons are lost, it is hydrogens being released
What should you realize about reduction?
As electrons are gained, hydrogen atoms are gained
What is reduction?
gain of electrons
What is the role of dehydrogenase in cellular respiration?
Dehydrogenase enzyme removes hydrogen from glucose
What is the role of NADH in cellular respiration?
NADH shuttles electrons
what are the reactants of oxidative phosphorylation?
starts with electrons shuttled by NADH and FADH2
what are the products of oxidative phosphorylation?
ends with A LOT of ATP
where does oxidative phosphorylation occur?
occurs in the mitochondrial membrane
what are the two sub-steps within oxidative phosphorylation?
the first step is the electron transport chain (etc) and the second is chemiosis
why are there so many folds (cristae) in the mitochondria?
it increases the surface area to allow more copies of the electron transport chain
where do the electrons come from? //// where do they end up (final electron acceptor)?
from the electron carriers NADH and FADH2 starting in glycolysis and continuing into the citric acid cycle//// oxygen is the final electron acceptor
Breathing
Gas exchange, take in O2 from air and release CO2 as a waste product
Cellular Respiration
Harvesting energy from food to use in the mitochondria
What happens to cellular respiration when agents such as cyanine, carbon monoxide, and rotenone disrupt cellular respiration?
The poisons block the electron transport chain which means it stops the carrier molecules from releasing energy for hydrogen molecules to get to the inter membrane space
How does ATP synthase use the H+ gradient?
Allows the hydrogen atoms to go through it from high to low gradient
Describe the H+ gradient across the inner mitochondrial membrane
The inner membrane has a higher concentration of hydrogen atoms then the mitochondrial matrix
What happens to H+ as electrons move through the transport chain?
It releases energy as it passes through each protein which allows the hydrogen to go through
single celled fungi
yeasts
what organisms use alcohol fermentation to process their food
yeasts and certain bacteria
how is alcohol fermentation different from cellular respiration?
it doesn’t not require oxygen(anaerobic)
pyruvate converts to ethanol, not acetyl coa
what are the waste products of alcohol fermentation?
2 carbon dioxide- makes alcohol bubbly
2 ethanol - waste product toxic to yeast cells
prokaryotes that require anaerobic conditions and are poisoned by oxygen (ex. in stagnant ponds or deep soil)
obligate anaerobe
bacteria that can make ATP either by fermentation or oxidative phosphorylation (ex. muscle cells, yeast cells)
facultative anaerobe
similarities btw lactic acid fermentation and alcohol fermentation
recycles NAD+
anaerobic respiration(no O2 requirement)
start w glycolysis
atp is produced as glucose is broken down
differences between lactic acid fermentation and alcohol fermentation
no co2 is produced in lactic acid but is in alcohol
lactic acid is produced instead of ethanol
what organisms use lactic acid fermentation
muscle cells and some bacteria
anaerobic respiration definition
producing cellular energy in the absence of oxygen
obligate anaerobes
require anaerobic conditions and are poisoned by oxygen (ex: prokaryotes in deep soil and stagnant ponds)
facultative anaerobe
can make atp by fermentation or oxidative phosphorylation depending if oxygen is available (ex: yeasts and muscle cells)
lactic acid fermentation products
oxidizes NADH and to NADH+ to produce LACTATE
products of alcohol fermentation
oxidizes NADH to NAD+ and produces ETHANOL and CO2
how are organic molecules (carbohydrates, lipids, proteins) processed to become fuel for cellular respiration
the organic molecules are broken down into their monomers so they can enter the cycle
carbohydrates – sugars – glucose
fats – glycerol and fatty acids
proteins – amino acids
